Campbell has won a Stanley Cup, but is also known for another distinction: When he was awarded the Lady Byng Trophy after the 2011-12 season, he ended a 58-season drought for defensemen, joining Red Kelly (1950-51, 1952-53, 1953-54) and Bill Quackenbush (1948-49) as the only NHL players at the position to earn the award for sportsmanship.

After being selected by the Buffalo Sabres in the sixth round (No. 156) in the 1997 NHL Draft, Campbell won the Memorial Cup with Ottawa of the Ontario Hockey League in 1998-99 and was named Canadian Major Junior Player of the Year. Campbell, who led OHL defensemen with 87 points that season, was the league MVP and an OHL First All-Star. He was awarded the George Parsons Trophy as the Memorial Cup Tournament's Most Sportsmanlike Player. Campbell also won a silver medal with Canada at the 1999 World Junior Championship.

Campbell made his NHL debut Oct. 2, 1999, for the Sabres against the Detroit Red Wings. Six days later, in his second NHL game, he got his first points with a goal and an assist against the Washington Capitals. In 2000-01 he appeared in eight games with Buffalo but tied for the lead among Rochester defensemen with 32 points and played in the AHL All-Star Classic.

Campbell spent his first full season in the NHL in 2002-03, and in 2005-06 led Buffalo defensemen with 12 goals, 22 assists and 34 points. He made his Stanley Cup Playoff debut that season, playing all 18 games as the Sabres reached the Eastern Conference Final. Campbell again led Buffalo defensemen in 2006-07 with 42 assists and 48 points. He got his first NHL playoff goals as part of a three-point game April 12, 2007, against the New York Islanders.

On Feb. 26, 2008, Campbell was traded to the San Jose Sharks with a 2008 seventh-round draft pick for Steve Bernier and a 2008 first-round pick. He signed as a free agent with the Chicago Blackhawks on July 1, 2008.

In 2008-09 Campbell led Blackhawks defensemen with 45 assists and 52 points, and led NHL defensemen in road assists (31) and points (35). Campbell had the primary assist on Patrick Kane's overtime goal in Game 6 of the 2010 Stanley Cup Final against the Philadelphia Flyers that won Chicago the Cup for the first time since 1961.

After the Blackhawks traded him to the Florida Panthers for Rostislav Olesz on June 24, 2011, Campbell had 53 points and six penalty minutes with the Panthers in 2011-12, his Lady Byng season.

An alternate captain for the Panthers in 2015-16, Campbell played his 1,000th NHL game April 5, 2016, against the Montreal Canadiens. He signed a one-year contract with Chicago as a free agent July 1, 2016.